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With single spur gears, a couple of gears forms a gear stage. In the event that you connect several equipment pairs one after another, this is known as a multi-stage gearbox. For each gear stage, the direction of rotation between the drive shaft and the output shaft is reversed. The entire multiplication factor of multi-stage gearboxes can be calculated by multiplying the ratio of every gear stage.
The drive speed is reduced or increased by the factor of the apparatus ratio, depending on whether it is a ratio to slow or a ratio to fast. In the majority of applications ratio to slow is required, because the drive torque is certainly multiplied by the entire multiplication element, unlike the drive speed.
A multi-stage spur gear can be realized in a technically meaningful method up to a gear ratio of approximately 10:1. The reason for this is based on the ratio of the number of teeth. From a ratio of 10:1 the driving gearwheel is extremely little. This has a negative influence on the tooth geometry and the torque that’s being transmitted. With planetary gears a multi-stage gearbox is incredibly easy to realize.
A two-stage gearbox or a three-stage gearbox can be achieved by merely increasing the length of the ring equipment and with serial arrangement of several individual planet stages. A planetary gear with a ratio of 20:1 can be manufactured from the individual ratios of 5:1 and 4:1, for instance. Instead of the drive shaft the planetary carrier multi stage planetary gearbox provides the sun equipment, which drives the next world stage. A three-stage gearbox is obtained by way of increasing the distance of the ring equipment and adding another world stage. A transmission ratio of 100:1 is obtained using individual ratios of 5:1, 5:1 and 4:1. Basically, all person ratios could be combined, which results in a huge number of ratio choices for multi-stage planetary gearboxes. The transmittable torque could be increased using extra planetary gears when performing this. The path of rotation of the drive shaft and the result shaft is often the same, so long as the ring gear or housing is fixed.
As the number of equipment stages increases, the efficiency of the overall gearbox is reduced. With a ratio of 100:1 the effectiveness is leaner than with a ratio of 20:1. To be able to counteract this scenario, the actual fact that the power loss of the drive stage is low should be taken into thought when using multi-stage gearboxes. That is achieved by reducing gearbox seal friction loss or having a drive stage that’s geometrically smaller, for instance. This also reduces the mass inertia, which can be advantageous in dynamic applications. Single-stage planetary gearboxes are the most efficient.
Multi-stage gearboxes may also be realized by combining various kinds of teeth. With a right position gearbox a bevel equipment and a planetary gearbox are simply just combined. Here too the overall multiplication factor may be the product of the individual ratios. Depending on the kind of gearing and the type of bevel equipment stage, the drive and the output can rotate in the same path.
Benefits of multi-stage gearboxes:
Wide variety of ratios
Constant concentricity with planetary gears
Compact style with high transmission ratios
Combination of different gearbox types possible
Wide range of uses
Disadvantages of multi-stage gearboxes (in comparison to single-stage gearboxes):
More complex design
Lower amount of efficiency
The automated transmission system is very crucial for the high-speed vehicles, where in fact the planetary or epicyclic gearbox is a standard feature. With the upsurge in design intricacies of planetary gearbox, mathematical modelling is becoming complex in character and therefore there is a need for modelling of multistage planetary gearbox including the shifting scheme. A random search-centered synthesis of three examples of freedom (DOF) high-acceleration planetary gearbox offers been shown in this paper, which derives an efficient gear shifting system through designing the tranny schematic of eight quickness gearboxes compounded with four planetary gear sets. Furthermore, by using lever analogy, the transmitting power movement and relative power effectiveness have been identified to analyse the gearbox style. A simulation-based tests and validation have been performed which show the proposed model can be effective and produces satisfactory change quality through better torque features while shifting the gears. A fresh heuristic solution to determine ideal compounding arrangement, predicated on mechanism enumeration, for developing a gearbox layout is proposed here.
Multi-stage planetary gears are widely used in many applications such as for example automobiles, helicopters and tunneling boring machine (TBM) due to their benefits of high power density and large reduction in a little volume [1]. The vibration and noise complications of multi-stage planetary gears are at all times the focus of interest by both academics and engineers [2].
The vibration of simple, single-stage planetary gears has been studied by many researchers. In the first literatures [3-5], the vibration framework of some example planetary gears are discovered using lumped-parameter models, however they didn’t give general conclusions. Lin and Parker [6-7] formally discovered and proved the vibration structure of planetary gears with equal/unequal planet spacing. They analytically classified all planetary gears settings into exactly three classes, rotational, translational, and planet modes. Parker [8] also investigated the clustering phenomenon of the three mode types. In the latest literatures, the systematic classification of modes were carried into systems modeled with an elastic continuum ring equipment [9], helical planetary gears [10], herringbone planetary gears [11], and high speed gears with gyroscopic effects [12].
The organic frequencies and vibration modes of multi-stage planetary gears have also received attention. Kahraman [13] set up a family group of torsional dynamics versions for substance planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic style of substance planetary gears of general explanation including translational degrees of freedom, which enables thousands of kinematic combinations. They mathematically proved that the modal features of substance planetary gears had been analogous to a straightforward, single-stage planetary gear system. Meanwhile, there are plenty of researchers focusing on the nonlinear dynamic characteristics of the multi-stage planetary gears for engineering applications, such as TBM [15] and wind mill [16].
According to the aforementioned models and vibration framework of planetary gears, many researchers concerned the sensitivity of the organic frequencies and vibration settings to program parameters. They investigated the effect of modal parameters such as for example tooth mesh stiffness, planet bearing stiffness and support stiffness on planetary equipment organic frequencies and vibration settings [17-19]. Parker et al. [20-21] mathematically analyzed the consequences of style parameters on organic frequencies and vibration modes both for the single-stage and substance planetary gears. They proposed closed-type expressions for the eigensensitivities to model parameter variants according to the well-defined vibration mode properties, and founded the relation of eigensensitivities and modal energies. Lin and Parker [22] investigated the veering of planetary equipment eigenvalues. They used the organized vibration modes to show that eigenvalue loci of different setting types generally cross and those of the same mode type veer as a model parameter is definitely varied.
However, many of the existing studies just referenced the method used for single-stage planetary gears to investigate the modal characteristics of multi-stage planetary gears, while the differences between both of these types of planetary gears had been ignored. Because of the multiple degrees of freedom in multi-stage planetary gears, more detailed division of natural frequencies are required to analyze the influence of different system parameters. The aim of this paper is to propose an innovative way of examining the coupled settings in multi-stage planetary gears to analyze the parameter sensitivities. Purely rotational degree of freedom models are used to simplify the analytical investigation of gear vibration while keeping the primary dynamic behavior produced by tooth mesh forces. In this paper, sensitivity of organic frequencies and vibration modes to both gear parameters and coupling shaft parameters of multi-stage planetary gears are studied.
1. Planetary gear sets are available in wide reduction gear ratios
2. Gear arranged can combine the same or different ratios
3. Planetary gear set is available in plastic, sintered metal, and steel, depending on different application
4. Hight efficiency: 98% efficiency at single decrease, 95% at double reduction
5. Planetary gear set torque range: Low torque, middle torque, high torque
6. Easy connecting with couplings, input shafts, output shafts
The planetary equipment is a special type of gear drive, where the multiple world gears revolve around a centrally arranged sun gear. The earth gears are mounted on a world carrier and engage positively in an internally toothed band gear. Torque and power are distributed among several planet gears. Sun gear, planet carrier and ring gear may either be generating, driven or fixed. Planetary gears are found in automotive building and shipbuilding, aswell as for stationary make use of in turbines and general mechanical engineering.
The GL 212 unit allows the investigation of the dynamic behaviour of a two-stage planetary gear. The trainer includes two planet gear pieces, each with three world gears. The ring equipment of the first stage is coupled to the earth carrier of the next stage. By fixing individual gears, you’ll be able to configure a complete of four different transmitting ratios. The apparatus is accelerated via a cable drum and a adjustable group of weights. The group of weights is elevated via a crank. A ratchet prevents the weight from accidentally escaping. A clamping roller freewheel enables free further rotation following the weight has been released. The weight is caught by a shock absorber. A transparent protective cover helps prevent accidental connection with the rotating parts.
To be able to determine the effective torques, the drive measurement measures the deflection of bending beams. Inductive velocity sensors on all drive gears allow the speeds to end up being measured. The measured values are transmitted directly to a Computer via USB. The data acquisition software is included. The angular acceleration could be read from the diagrams. Effective mass occasions of inertia are determined by the angular acceleration.
investigation of the powerful behaviour of a 2-stage planetary gear
three planet gears per stage
four different transmission ratios possible
gear is accelerated via cable drum and adjustable set of weights
weight raised yourself crank; ratchet prevents accidental release
clamping roller freewheel enables free further rotation following the weight has been released
shock absorber for weight
transparent protective cover
drive measurement on different equipment stages via 3 bending bars, display via dial gauges
inductive speed sensors
GUNT software program for data acquisition via USB under Windows 7, 8.1, 10
Technical data
2-stage planetary gear
module: 2mm
sunlight gears: 24-tooth, d-pitch circle: 48mm
planet gears: 24-tooth, d-pitch circle: 48mm
band gears: 72-tooth, d-pitch circle: 144mm
Drive
set of weights: 5…50kg
max. potential energy: 245,3Nm
Load at standstill
weight forces: 5…70N
Measuring ranges
speed: 0…2000min-1
230V, 50Hz, 1 phase
230V, 60Hz, 1 stage; 120V, 60Hz, 1 phase
UL/CSA optional
he most basic type of planetary gearing involves three sets of gears with different levels of freedom. World gears rotate around axes that revolve around a sunlight gear, which spins in place. A ring gear binds the planets externally and is completely set. The concentricity of the earth grouping with the sun and ring gears implies that the torque carries through a straight series. Many power trains are “comfortable” lined up straight, and the lack of offset shafts not merely decreases space, it eliminates the need to redirect the power or relocate other elements.
In a straightforward planetary setup, input power turns sunlight gear at high acceleration. The planets, spaced around the central axis of rotation, mesh with sunlight along with the fixed ring equipment, so they are pressured to orbit because they roll. All the planets are mounted to an individual rotating member, known as a cage, arm, or carrier. As the earth carrier turns, it delivers low-speed, high-torque output.
A set component isn’t often essential, though. In differential systems every member rotates. Planetary arrangements like this accommodate a single output powered by two inputs, or an individual input generating two outputs. For instance, the differential that drives the axle within an vehicle is certainly planetary bevel gearing – the wheel speeds represent two outputs, which must differ to take care of corners. Bevel equipment planetary systems operate along the same theory as parallel-shaft systems.
Even a simple planetary gear train provides two inputs; an anchored ring gear represents a constant insight of zero angular velocity.
Designers can go deeper with this “planetary” theme. Compound (instead of simple) planetary trains possess at least two world gears attached in range to the same shaft, rotating and orbiting at the same acceleration while meshing with different gears. Compounded planets can possess different tooth quantities, as can the gears they mesh with. Having this kind of options greatly expands the mechanical opportunities, and allows more reduction per stage. Compound planetary trains can easily be configured so the world carrier shaft drives at high swiftness, while the reduction issues from the sun shaft, if the designer prefers this. One more thing about compound planetary systems: the planets can mesh with (and revolve around) both fixed and rotating external gears simultaneously, therefore a ring gear is not essential.
Planet gears, for his or her size, engage a whole lot of teeth as they circle the sun gear – therefore they can certainly accommodate many turns of the driver for every result shaft revolution. To execute a comparable decrease between a typical pinion and gear, a sizable gear will have to mesh with a fairly small pinion.
Basic planetary gears generally provide reductions as high as 10:1. Substance planetary systems, which are more elaborate than the simple versions, can offer reductions many times higher. There are obvious ways to further decrease (or as the case may be, increase) speed, such as for example connecting planetary stages in series. The rotational output of the initial stage is from the input of another, and the multiple of the individual ratios represents the ultimate reduction.
Another option is to introduce regular gear reducers right into a planetary teach. For example, the high-acceleration power might go through an ordinary fixedaxis pinion-and-gear set prior to the planetary reducer. This kind of a configuration, known as a hybrid, is sometimes preferred as a simplistic option to additional planetary levels, or to lower input speeds that are too much for some planetary units to take care of. It also has an offset between the input and output. If the right angle is necessary, bevel or hypoid gears are occasionally mounted on an inline planetary system. Worm and planetary combinations are uncommon because the worm reducer by itself delivers such high adjustments in speed.